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A challenging case: A dog with nonhealing corneal ulcers

Corneal ulcers usually heal rapidly with appropriate treatment, but this Labrador developed two that were slow to heal. A technique used commonly in people—diamond burr superficial keratectomy—appeared to help in this case.

A 12-year-old 74-lb (33.7-kg) spayed female Labrador retriever was presented to the Colorado State University James L. Voss Veterinary Teaching Hospital for evaluation of a superficial corneal ulcer of the right eye of three weeks' duration. Despite medical therapy by the referring veterinarian, consisting of topical antibiotics of unknown type, atropine, and autogenous serum, the eye had not improved.

Vital Stats

The dog had been healthy all its life and had never received any medical treatments. It was current on its vaccinations and heartworm preventive. No blood work or urinalysis had been done within the prior year.

INITIAL PRESENTATION

A complete ophthalmic examination revealed a raised, pink mass (measuring 4 mm x 7 mm) of granulation-like tissue on the right corneal surface and moderate iris atrophy and nuclear sclerosis in both eyes. Mild conjunctival hyperemia was present in the right eye, and small, superficial corneal blood vessels extended from the lateral limbus to the centrally located mass. The pink mass was adjacent to a corneal area that appeared ulcerated. Fluorescein staining of the cornea confirmed that this area was a superficial corneal ulcer. The results of Schirmer tear tests and tonometry were normal in both eyes. The results of the remainder of the ophthalmic and physical examinations were normal.

Diagnosis

We diagnosed a spontaneous chronic corneal epithelial defect (SCCED) in the right eye with secondary granulation tissue formation. The SCCED diagnosis was based on the fact that the ulcer was superficial and undermined (had a surrounding lip of epithelium that was not attached to the anterior corneal stroma) and was not healing. In addition, we had ruled out other causes of nonhealing ulcers, such as keratoconjunctivitis sicca, persistent foreign bodies, infection, and eyelid anomalies such as distichiasis, ectopic cilia, and entropion.1,2

Treatment

Treatment for the ulcer consisted of applying a topical anesthetic and aggressive removal of the undermined corneal epithelium. This was done by first rubbing off the tissue with a sterile, cotton-tipped applicator followed by superficial débridement of the anterior stroma with a 3.5-mm, low-torque, diamond-tipped, motorized burr.3,4

The dog was discharged with instructions for the owner to administer topical 1% morphine ophthalmic drops (compounded by the veterinary teaching hospital's pharmacy) three times a day in the right eye.5 The morphine was used to decrease the pain that is often present after débridement. A neomycin-polymyxin-gramicidin ophthalmic ointment was also prescribed four times a day in the right eye for infection prophylaxis.

Follow-up

Two weeks later, the right cornea no longer retained fluorescein stain; however, a partially transparent scar remained in the dorsotemporal quadrant. Antibiotics were discontinued, and the defect was considered healed.